As far as I can tell the 5 isn't offered in the US yet. Murena uses e/os (a sort of de-googled android os), so apps like gmail are not native. They say that their store pulls from the google play store though, so any apps you've gotten through that should be compatible.
Depends on what you're looking for. It's storage is expandable up to 2 TERABYTES, Gives Android updates for almost 10 years from what I remember ( these updates will be supported even after their chip manufacturer, Qualcomm stops support). An additional bonus is that since all of their parts are available to buy at a fairly cheap price, you don't have to spend that much money all time trying to replace the screen or the speaker or any other part of the phone. UNLIKE my Pixel 7 pro that costs fucking $350 to replace its screen.